JP5065149B2 - Portable machine - Google Patents

Description

  The present invention relates to a portable device that performs predetermined wireless communication with a specific communication target.

Conventionally, as shown in Patent Document 1, for example, an electronic key that locks and unlocks the lock device through a predetermined wireless communication with a communication target such as a lock device provided in a vehicle or a house has been adopted. ing. A circuit board is accommodated in the case of the electronic key. On the circuit board, an identification code corresponding to the lock device is stored, and a control circuit for performing transmission control of the identification code and a transmission antenna for performing wireless communication with the lock device are mounted. The control circuit transmits the identification code to the lock device through the transmission antenna. The locking device determines whether or not the identification code included in the radio wave transmitted from the transmission antenna of the electronic key matches the identification code stored in the locking device, and performs locking and unlocking on the condition that they match. .
JP 2002-322841

  By the way, from the viewpoint of improving portability, portable devices still tend to be smaller and thinner. Along with this, miniaturization of the transmission antenna provided in the case of the portable device is also required. However, generally, when the transmission antenna becomes small, the intensity of the radio wave output from the portable device decreases. For this reason, in order to ensure sufficient output intensity of radio waves transmitted from the portable device during wireless communication while reducing the size of the portable device, the output intensity of radio waves transmitted from the transmitting antenna during wireless communication is efficiently improved. It is necessary to let

  The present invention has been made in view of such circumstances, and it is an object of the present invention to provide a portable device capable of efficiently improving the output intensity of a radio wave transmitted during wireless communication.

The invention according to claim 1 includes a case made of a non-conductive material, and a transmission antenna that is provided inside the case and transmits a unique identification code of itself to a communication target wirelessly, In the portable device that operates the specific device corresponding to the communication target on condition that the verification of the identification code matches, the metal member having an open loop shape provided in an annular shape and divided by a slit in the circumferential direction thereof The metal member is a design decorating part by a member constituting a metal decorating part provided on the design surface of the case so as to satisfy the design of the appearance of the portable device, and the transmitting antenna is the slit When the annular design decoration portion is developed in a straight line , the gist is that it is arranged in the vicinity of the central portion of the entire length .

In general, when there is a metal near the antenna, radio waves transmitted from the antenna during wireless communication with the communication target are affected by the metal. Therefore, the present application is to provide a metal member in a portable device, effectively use the metal member as a transmission antenna in wireless communication with a communication target, and improve the output intensity of a transmission radio wave transmitted from the portable device. The person came up with the idea. According to the present invention, the metal member is placed in the central portion in the longitudinal direction of the metal member, that is, in the vicinity of the position where the current distribution based on the voltage induced in the metal member during wireless communication with the communication target becomes the largest. A transmission antenna that serves as a feeding point for the member is disposed. For this reason, compared with the case where the transmission antenna is arrange | positioned in the edge part vicinity of the longitudinal direction of the metal member with which electric current distribution becomes small, coupling | bonding with a metal member and a transmission antenna becomes large. Therefore, the metal member can be effectively used as a transmission antenna during wireless communication with a communication target, and the output intensity of the portable device can be improved efficiently.
In addition, by using the metal decoration provided on the design surface of the case as a transmitting antenna to satisfy the design of the appearance of the portable device, the output strength of the portable device can be increased without special provision of other metal members. It can be improved efficiently.

According to a second aspect of the present invention, in the portable device according to the first aspect, the case is formed in a flat shape, and the metal member is viewed from a direction along the thickness direction of the case. The gist of the present invention is to have an open loop shape that is provided in an annular shape extending along the edge of the ring and is divided in the circumferential direction.

  According to the present invention, since the case is formed in a flat shape, the outer surface in the thickness direction of the case is larger than the outer surface in the flat direction of the case. Therefore, by providing the metal member in an annular shape extending along the edge of the case when viewed from the direction along the thickness direction of the case, the area of the metal member as a transmission antenna can be set large. Therefore, the metal member can be more effectively used as a transmission antenna in wireless communication with a communication target, and the output intensity of the portable device can be improved efficiently.

  ADVANTAGE OF THE INVENTION According to this invention, the portable device which can improve the output intensity of the electromagnetic wave transmitted in radio | wireless communication efficiently can be provided.

Hereinafter, an embodiment in which the present invention is embodied in an electronic key used for opening and closing a door lock in an electronic key system of a vehicle will be described with reference to the drawings.
<Outline of electronic key system>
As shown in FIG. 1, the electronic key system 1 includes an electronic key 2 as a portable device and a locking / unlocking control device 3 as a communication target mounted on a vehicle. When the user has the electronic key 2 and approaches a predetermined area (communication area) of the vehicle, the electronic key 2 receives the request signal Sr transmitted from the locking / unlocking control device 3. This request signal Sr is a signal for requesting the electronic key 2 to transmit the ID code. When receiving the request signal Sr, the electronic key 2 transmits an ID signal Si including its own ID code recorded in advance. When receiving the ID signal Si transmitted from the electronic key 2, the locking / unlocking control device 3 collates the ID code on the electronic key 2 side included in the ID signal Si with the vehicle-side ID code stored in advance. The door lock is unlocked on condition that both ID codes match. On the other hand, when the user holds the electronic key 2 and moves away from the predetermined area away from the vehicle, the locking / unlocking control device 3 cannot receive the ID signal Si transmitted from the electronic key 2. The locking / unlocking control device 3 locks the door of the vehicle on condition that the ID signal Si on the electronic key 2 side cannot be received. Thus, the door is locked and unlocked without the user touching the vehicle.

<Electronic key>
As shown in FIG. 2, the case 4 of the electronic key 2 is made of a non-conductive material such as resin, and is formed in a flat shape that forms a rectangle in a plan view (as viewed from above in FIG. 2). As shown in FIG. 3, the case 4 is composed of an upper case 5 and a lower case 6 each formed in a box shape having an opening, and an internal storage formed when these openings are assembled in a state of abutting each other. A circuit board 7 is accommodated in the space 4a. Various electronic components for performing predetermined wireless communication and the like with the vehicle (more precisely, the locking / unlocking control device 3) are mounted on the circuit board 7.

  A step portion 5b is annularly recessed at the edge of the surface 5a of the upper case 5. An upper side decoration metal 8 is attached to the step portion 5b to give the electronic key 2 a high-class feeling, that is, a glitter design as seen in a noble metal product. The upper decorative metal 8 is formed so as to be flush with the central portion 5 c by being attached to the step portion 5 b of the upper case 5. The upper side decorative metal 8 is made of, for example, a metal material such as aluminum or iron, and the surface thereof is plated for producing glitter. The upper decorative metal 8 is formed to have an open loop shape in which a belt-like plate is provided in an annular shape extending along the periphery of the upper case 5 and is divided in the circumferential direction. Specifically, one slit 9 a having a long and narrow shape for dividing the upper side decoration metal 8 is formed in the upper side decoration metal 8. The slit 9a is formed in the center part of the short first first short side 8a (the back side in FIG. 3) among the four sides of the upper side decorative metal 8.

  In addition, the central portion 5c of the surface 5a of the upper case 5 has a lock switch 4b that is operated when the door of the vehicle is locked by a button operation with the electronic key 2, and a button operation with the electronic key 2 to An unlock switch 4c that is operated when unlocking the door lock is provided.

  As shown in FIG. 3, at the edge of the surface 6a of the lower case 6 (see FIG. 4 (b)), a step portion 6b is annularly formed in the same manner as the upper case 5, and the step portion 6b The lower decorative metal 10 is attached. The lower decorative metal 10 is formed to be flush with the central portion 6c (see FIG. 4B) by being attached to the step portion 6b of the lower case 6. The lower decorative metal 10 is made of a metal material such as aluminum or iron, for example, like the upper decorative metal 8, and the surface thereof is plated for producing glitter. The lower side decorative metal 10 is formed to have an open loop shape in which a belt-like plate is provided in an annular shape extending along the periphery of the lower case 6 and is divided in the circumferential direction. Specifically, the lower decorative metal 10 is formed with one slit 9b having a long and narrow shape for dividing the lower decorative metal 10 in the same manner as the upper decorative metal 8. The slit 9b is formed in the central portion of the first short side 10a (the back side in FIG. 3) having a short length among the four sides of the lower decorative metal 10. The upper side decorative metal 8 and the lower side decorative metal 10 are arranged so as to completely overlap when viewed from the surfaces 5a, 6a of the case 4 (the upper case 5 and the lower case 6). In addition, the upper side decoration metal 8 and the lower side decoration metal 10 correspond to the metal decoration part as a metal member. The electronic key 2 of this embodiment includes a surface 5a of the upper case 5 provided with an upper side decorative metal (hereinafter referred to as a decorative metal) 8 and a lower side decorative metal (hereinafter referred to as a decorative metal). The surface 6a of the lower case 6 provided with 10 is a design surface. As described above, since the case 4 is formed in a flat shape, the surfaces 5 a and 6 a of the case 4 (the upper case 5 and the lower case 6), which are the outer surfaces in the thickness direction of the case 4, It is larger than the outer side surface 4d in the flat direction. For this reason, compared with the case where it provides in the outer side surface 4d of the flat direction of case 4, it is possible to set the area of the decoration metals 8 and 10 large.

  As shown in FIG. 3, the circuit board 7 is formed in a rectangular flat plate shape. A transmission antenna 11, a reception circuit (not shown), a control circuit (not shown), and a transmission circuit (not shown) are mounted on a surface 7 a on the upper case 5 side of the circuit board 7. A receiving antenna (not shown) and a power circuit (not shown) are mounted on the side surface 7b. The receiving circuit demodulates the request signal Sr (see FIG. 1) received via the receiving antenna, and sends the demodulated request signal Sr to the control circuit. In order to respond to the demodulated request signal Sr, the control circuit sends an ID signal Si (see FIG. 1) including its own ID code stored in advance to the transmission circuit. The transmission circuit modulates the ID signal and transmits it through the transmission antenna 11. Further, when the control circuit detects that the lock switch 4b is pushed, the lock request including the ID code and the lock request for setting the door lock of the unlocked vehicle to the locked state is placed. The signal Sa (see FIG. 1) is sent to the transmission circuit and transmitted via the transmission antenna 11. In addition, when the control circuit detects that the unlock switch 4c has been pushed, it puts its own unique ID code and an unlocking request for unlocking the door lock of the locked vehicle. An unlock request signal Sb (see FIG. 1) is sent to the transmission circuit and transmitted via the transmission antenna 11.

  As shown in FIGS. 4A and 4B, the transmission antenna 11 is formed of a pattern antenna that is formed by printing a metal plate directly on the circuit board 7 as an antenna wire (antenna pattern). ing. The transmission antenna 11 is provided on one end side in the longitudinal direction of the circuit board 7 (the lower end side in FIGS. 4A and 4B). The circuit board 7 is on the side opposite to the slits 9a, 9b of the decorative metals 8, 10 when viewed from the front surfaces 5a, 6a of the case 4 (lower side in FIGS. 4A and 4B). In the center part of the second short sides 8b and 10b, in other words, when the annular decorative metals 8 and 10 are expanded linearly, in the vicinity of the central part in the longitudinal direction (full length) of the expanded decorative metals 8 and 10 The case 4 is accommodated so that the transmission antenna 11 is arranged. Further, the circuit board 7 is arranged so that the entire transmission antenna 11 does not overlap with the decorative metals 8 and 10 when viewed from the front surfaces 5 a and 6 a of the case 4. As described above, since the case 4 is formed in a flat shape, the surfaces 5 a and 6 a of the case 4 (the upper case 5 and the lower case 6), which are the outer surfaces in the thickness direction of the case 4, It is larger than the outer side surface 4d in the flat direction. For this reason, it is easy to arrange the transmitting antenna 11 at a position where the transmitting antenna 11 does not overlap with the decorative metals 8 and 10 when viewed from the front surfaces 5 a and 6 a of the case 4. Moreover, compared with the case where the decoration metals 8 and 10 are provided in the outer side surface 4d of the flat direction of the case 4, the area of the decoration metals 8 and 10 can be set large.

  By the way, the decorative metal 8, 10 formed of a metal material such as aluminum or iron, for example, is assumed to be a continuous member along the edge of the surface 5a, 6a of the case 4, for example, the surface 5a of the case 4. In the case of taking a closed loop shape when viewed from the side of 6a, the radio wave transmitted from the transmitting antenna 11 when performing wireless communication between the electronic key 2 and the vehicle (locking / unlocking control device 3) is used as a decorative metal 8, When 10 is received, an eddy current (see FIG. 4A) flows through the decorative metals 8 and 10. When an eddy current flows through the decorative metals 8 and 10, the radio wave transmitted from the transmission antenna 11 is canceled out by the magnetic flux generated by the eddy current, and the antenna efficiency is reduced, and the electronic key 2 and the vehicle (the locking / unlocking control device 3). ) Is adversely affected, which is undesirable from the viewpoint of securing wireless communication performance.

  Therefore, the decorative metals 8 and 10 are provided with slits 9a and 9b, and the decorative metals 8 and 10 are divided in the direction along the edges of the front surfaces 5a and 6a of the case 4 so that the decorative metals 8 and 10 are separated. In this case, the member has a divided shape that is not continuous, that is, an open loop shape. The decorative metals 8 and 10 having such an open loop shape have a characteristic that an eddy current hardly occurs in the decorative metals 8 and 10 even when receiving a radio wave transmitted from the transmission antenna 11. Therefore, even if the decorative metal 8 or 10 is used to decorate the electronic key 2 in order to ensure the design of the electronic key 2, if the slits 9a and 9b are formed in the decorative metal 8 or 10, the decorative metal is used. Generation of eddy currents at 8 and 10 is suppressed, and sufficient wireless communication performance of the electronic key 2 is ensured.

  By the way, such an electronic key 2 is desired to be further downsized in order to improve its portability. Here, if the case 4 is made smaller in order to reduce the size of the electronic key 2, the space for accommodating the transmission antenna 11 in the case 4 becomes narrow, and the transmission antenna 11 needs to be made smaller. However, normally, the smaller the transmission antenna 11 is, the smaller the output intensity of the transmission radio wave transmitted from the electronic key 2 during wireless communication is. For this reason, in order to obtain the output intensity of the transmission radio wave sufficient to ensure the communication performance between the electronic key 2 and the locking / unlocking control device 3, it is necessary to enlarge the transmission antenna 11 to some extent. This hinders downsizing of the electronic key 2.

  On the other hand, for example, a metal such as aluminum or iron is used for decorating the glitter design, so that the radio wave transmitted from the transmission antenna 11 during the wireless communication with the locking / unlocking control device 3 is applied to the decorative metals 8 and 10. As a result, the output intensity of the transmission radio wave transmitted from the electronic key 2 to the locking / unlocking control device 3 changes. Specifically, when a radio wave is transmitted from the transmission antenna 11 during wireless communication between the electronic key 2 and the locking / unlocking control device 3, an induced current is generated in the decorative metals 8 and 10, and the radio wave is radiated. That is, the transmission antenna 11 and the decorative metals 8 and 10 are combined, and the decorative metals 8 and 10 function as a transmission antenna.

  Here, the current distribution induced in the decorative metals 8 and 10 that have received the radio wave transmitted from the transmitting antenna 11 during the wireless communication between the electronic key 2 and the locking / unlocking control device 3 is shown in FIG. Show. In FIG. 5A, the horizontal axis indicates the position in the longitudinal direction when the decorative metals 8 and 10 are linearly expanded, and the vertical axis is based on the voltage induced in the decorative metals 8 and 10. Indicates the current value. 5 (a) and 5 (b), the corresponding three places of the decorative metals 8 and 10 and the annular decorative metals 8 and 10 expanded in a straight line are indicated by alphabets “A”, “B”, Indicated by “C”. As shown in FIG. 5A, the current induced in the decorative metals 8 and 10 is at the positions at both ends (positions indicated by A and C in FIGS. 5A and 5B). It becomes the smallest and becomes the largest at the center (the position indicated by B in FIGS. 5A and 5B). Therefore, the position where the current distribution based on the voltage induced in the decorative metals 8 and 10 becomes the largest in the wireless communication with the locking and unlocking control device 3, that is, the center in the longitudinal direction of the decorative metals 8 and 10. By arranging the transmission antenna 11 in the vicinity of the portion (the position indicated by B in FIGS. 5A and 5B), the transmission antenna 11 can be used for wireless communication between the electronic key 2 and the locking / unlocking control device 3. And the magnetic coupling between the decorative metals 8 and 10 are increased. For this reason, in this Embodiment, in the center part of the longitudinal direction of the decoration metals 8 and 10, ie, the center part vicinity of the 2nd short sides 8b and 10b on the opposite side to the slits 9a and 9b of the decoration metals 8 and 10. The transmitting antenna 11 serving as a feeding point to the decorative metals 8 and 10 is arranged. Thereby, in the wireless communication with the locking / unlocking control device 3, the decorative metals 8 and 10 effectively function as a transmission antenna, and the output intensity of the transmission radio wave transmitted from the electronic key 2 is improved. . Even if, for example, the transmission antenna 11 housed in the case 4 is made smaller in order to reduce the size of the electronic key 2, even if the output intensity of the transmission antenna 11 itself is reduced, the decorative metal 8 , 10 are effectively used as transmitting antennas, so that the communication performance between the electronic key 2 and the locking / unlocking control device 3 is ensured.

  Next, with reference to FIG. 6, the amount of change in the gain of the electronic key 2 due to the difference in the position of the transmission antenna 11 as viewed from the front surfaces 5a and 6a of the case 4 will be considered. FIG. 6 shows the present embodiment in which the transmitting antenna 11 is arranged in the vicinity of the center of the second short sides 8b, 10b on the opposite side of the slits 9a, 9b of the decorative metals 8, 10 as shown in FIG. 7 (a). As shown in FIG. 7B, the transmitting antenna 11 is disposed in the vicinity of the center of the first short sides 8a and 10a provided with the slits 9a and 9b of the decorative metals 8 and 10, as shown in FIG. A graph showing the result of simulation by the inventor of the amount of change in gain of the electronic keys 2 and 20 with respect to the width d of the slits 9a and 9b of the decorative metals 8 and 10 for the electronic key 20 to be compared It is. In the graph of FIG. 6, the horizontal axis indicates the width (slit width) d of the slits 9 a and 9 b of the decorative metals 8 and 10, and the vertical axis indicates the amount of change in the gain of the electronic keys 2 and 20. The amount of change in the gain of the electronic keys 2 and 20 is the gain of the electronic keys 2 and 20 based on the gain of the circuit board 7 alone. In FIG. 6, the gain change amount of the electronic key 2 (see FIG. 7A) of the present embodiment is indicated by □, and the gain change of the electronic key 20 to be compared (see FIG. 7B) is shown. The quantity is indicated by ●. In FIGS. 7A and 7B, the lock switch 4b and the unlock switch 4c are omitted.

  As shown in FIG. 6, when the size of the width d of the slits 9 a and 9 b of the decorative metals 8 and 10, that is, the shapes of the decorative metals 8 and 10 are matched, the electronic key 2 of the present embodiment The amount of gain change is larger than the amount of gain change of the electronic key 20 to be compared. Therefore, regardless of the shape of the decorative metals 8 and 10, if the transmitting antenna 11 is disposed in the vicinity of the central portion of the second short sides 8b and 10b, which is the central portion in the longitudinal direction of the decorative metals 8 and 10 (FIG. 7). (See (a)), than the case where the transmitting antenna 11 is arranged near the center of the first short sides 8a, 10a that are the ends in the longitudinal direction of the decorative metals 8, 10 (see FIG. 7B), The output intensity of the electronic key 2 can be improved. For this reason, even when the output intensity of the transmission antenna 11 itself is reduced by making the transmission antenna 11 accommodated in the case 4 smaller in order to reduce the size of the electronic key 2, for example, the decorative metal By effectively using 8 and 10 as transmission antennas, it is possible to obtain a sufficient output intensity to ensure communication performance between the electronic key 2 and the locking / unlocking control device 3. Therefore, it is possible to reduce the size of the transmission antenna 11 accommodated in the case 4, and hence the size of the electronic key 2, and improve the portability of the electronic key 2.

Next, the operational effects of the above embodiment will be described below.
(1) The central portion of the decorative metals 8 and 10 in the longitudinal direction, that is, the belly in which the current distribution based on the voltage induced in the decorative metals 8 and 10 during wireless communication with the locking and unlocking control device 3 is the largest. A transmitting antenna 11 serving as a feeding point to the decorative metals 8 and 10 is disposed in the vicinity of the position where For this reason, the electronic key 2 is compared with the electronic key 20 to be compared (see FIG. 7B) in which the transmitting antenna 11 is disposed in the vicinity of the longitudinal ends of the decorative metals 8 and 10 with a small current distribution. In this case, the coupling between the decorative metals 8 and 10 and the transmitting antenna 11 is increased. Therefore, in the wireless communication with the locking / unlocking control device 3, the decorative metals 8 and 10 can be used effectively (positively) as a transmission antenna, and the output intensity of the electronic key 2 can be efficiently increased. Can be improved.

  (2) Moreover, the output intensity | strength of the said electronic key 2 improves by using the decorative metals 8 and 10 effectively (actively) as a transmission antenna. For this reason, even when the output intensity of the transmission antenna 11 itself is reduced by making the transmission antenna 11 accommodated in the case 4 smaller in order to reduce the size of the electronic key 2, for example, the decorative metal By effectively using 8 and 10 as transmission antennas, it is possible to obtain a sufficient output intensity to ensure communication performance between the electronic key 2 and the locking / unlocking control device 3. Therefore, it is possible to reduce the size of the transmission antenna 11 accommodated in the case 4, and hence the size of the electronic key 2, and improve the portability of the electronic key 2.

  (3) By using the decorative metals 8 and 10 provided on the surfaces 5a and 6a of the case 4 as the transmitting antenna so as to satisfy the design of the appearance of the electronic key 2, there is no need to specially provide other metal members. The output intensity of the electronic key 2 can be improved efficiently.

  (4) Since the case 4 is formed in a flat shape, the outer surface in the thickness direction of the case 4 is larger than the outer surface in the flat direction of the case 4. Therefore, by providing the decorative metals 8 and 10 in an annular shape extending along the edge of the case 4 when viewed from the direction along the thickness direction of the case 4, the area of the decorative metals 8 and 10 as the transmitting antenna is increased. Can be set large. Therefore, in the wireless communication with the locking / unlocking control device 3, the decorative metals 8 and 10 can be used more effectively as a transmission antenna, and the output intensity of the electronic key 2 can be improved efficiently. Can do.

  (5) The transmission antenna 11 accommodated in the case 4 of the electronic key 2 is arranged so that the entire portion does not overlap the decorative metals 8 and 10 when viewed from the front surfaces 5a and 6a of the case 4. Here, radio waves transmitted from a portion of the transmitting antenna 11 that is arranged so as not to overlap the decorative metals 8 and 10 are not easily affected by the decorative metals 8 and 10. For this reason, by arrange | positioning so that the whole transmission antenna 11 may not overlap with the decoration metals 8 and 10 like this Embodiment, the fall of the antenna efficiency by providing the decoration metals 8 and 10 is avoided as much as possible. can do.

  (6) The decorative metals 8 and 10 are provided in an annular shape extending along the edges of the surfaces 5a and 6a when viewed from the surfaces 5a and 6a side of the case 4, and have an open loop shape divided in the circumferential direction. For example, the coupling between the transmitting antenna 11 and the decorative metals 8 and 10 can be increased as compared with the case where the decorative metals 8 and 10 are provided in a straight line. Therefore, in the wireless communication with the locking / unlocking control device 3, the decorative metals 8 and 10 can be used more effectively as a transmission antenna, and the output intensity of the electronic key 2 can be improved efficiently. Can do.

In addition, you may change this Embodiment as follows.
-In above-mentioned embodiment, although the decoration metals 8 and 10 as a metal member were provided in the surface (design surface) 5a, 6a of the case 4, it is not limited to such an aspect. For example, as shown in FIG. 8, a metal member 31 having an open loop shape may be embedded in the case 30 of the electronic key 2a. Moreover, in the said embodiment, although the decoration metals 8 and 10 as a metal member were formed in strip | belt shape, the cross-sectional shape of the decoration metals 8 and 10 can be changed suitably, for example, even if it forms in a cross-sectional circle shape. Good.

In the above embodiment, the transmission antenna 11 is arranged so as not to overlap the decorative metals 8 and 10, but may be arranged so that a part of the transmission antenna 11 overlaps.
In the above embodiment, the decorative metals 8 and 10 are formed on the surfaces 5a and 6a of the case 4 so as to form a substantially ring shape along the peripheral edge of the case 4, but the present invention is not limited to such an embodiment. For example, like the electronic key 2 b shown in FIG. 9, two slits 42 and 43 are provided in the decorative metals 41 a and 41 b (41) provided on the surface of the case 40, and they are straight along the side edges of the case 40. You may form so that it may form. In this case, the transmission antenna 11 is arranged in the center of the case 40 so that the transmission antenna 11 is arranged in the vicinity of the central portion in the longitudinal direction of each decorative metal 41.

In the above embodiment, one slit 9a, 9b is provided for each decorative metal 8, 10, but two or more slits may be provided.
In the above embodiment, the case 4 is formed in a flat shape that forms a rectangle in a plan view, but is not limited to such a mode, and may be formed in a triangle or a circle in a plan view, for example. Moreover, in the said embodiment, although the case 4 was formed in flat shape, you may form a case in a cube shape, for example.

  In the above embodiment, the outer side surfaces (surfaces 5a and 6a) in the thickness direction of the case 4 are used as design surfaces, but the outer side surface 4d in the flat direction of the case 4 may be used as design surfaces. Moreover, in the said embodiment, although the decoration metals 8 and 10 were provided in the upper case 5 of the case 4, and the surfaces 5a and 6a of the lower case 6, you may provide a decoration metal only in any one.

In the above embodiment, the lock switch 4b and the unlock switch 4c are provided on the electronic key 2, and the door lock can be locked and unlocked by these operations, but may be omitted.
To-electronic key 2, equipped with a transponder may be performed ID verification in between the transponder and the unlocking control device 3.

  In the above embodiment, the door lock of the vehicle as the corresponding device is unlocked and unlocked by wireless communication between the electronic key 2 and the locking / unlocking control device 3, but the electronic key 2 and the engine control are controlled. The start of the engine as a corresponding device may be permitted by wireless communication with the device. In this case, the engine control device corresponds to the communication target of the present invention.

In the above embodiment, the electronic key system 1 of the vehicle is embodied as an electronic key used for opening and closing the door lock, but may be embodied as an electronic key system such as a house.
In the above embodiment, the present invention is applied to the case where the electronic key 2 is downsized. However, the present invention is not limited to such a case, and the output strength depends on the specification of the electronic key 2 (required communication area size). It may be applied when improvement is required.

The schematic block diagram of the electronic key system of a vehicle. The perspective view which shows the external appearance shape of an electronic key. The perspective view which shows the case structure of an electronic key. (A) The top view which looked at the electronic key from the front side, (b) The top view which looked at the electronic key from the back side. (A) The graph which shows distribution of the electric current induced by a decoration metal, (b) The top view of an electronic key. The graph which illustrates the simulation result by an inventor about the relationship between the position of a transmission antenna, and the variation | change_quantity of the gain of an electronic key. (A) The top view which shows the position of the transmission antenna in the electronic key of this Embodiment, (b) The top view which shows the position of the transmission antenna in the electronic key of a comparison object. The top view which shows another example of an electronic key. The top view which shows another example of an electronic key.

Explanation of symbols

2, 2a, 2b ... electronic key as a portable device, 3 ... locking / unlocking control device as communication object, 4, 30, 40 ... case, 5a, 6a ... surface as design surface, 8, 10 ... metal member and metal Decorative metal as a decorative part, 9a, 9b ... slit, 31 , 41 ... metal member, 11 ... transmitting antenna.

Claims (2)

A case made of a non-conductive material and a transmission antenna that is provided inside the case and wirelessly transmits its own identification code to the communication target, and the verification of the identification code matches on the communication target side In a portable device that operates a specific device corresponding to the communication target on condition that
Provided with a metal member having an open loop shape provided in a ring and divided by a slit in the circumferential direction thereof,
The metal member is a design decoration part by a member constituting a metal decoration part provided on the design surface of the case so as to satisfy the design of the appearance of the portable device,
The transmitting antenna is an opposite side of the slit, when deployed the design decorative portion of the annular straight, portable device which is characterized in that it is arranged near the central portion of its length. The portable device according to claim 1 ,
The case is formed in a flat shape,
The metal member is provided in an annular shape extending along an edge of the case as viewed from a direction along the thickness direction of the case and has an open loop shape divided in the circumferential direction. Machine.

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